To conserve weight and space in engine blocks, it is desirable to minimize the spacing between the bores. The closer together the bores are, the more difficult it is to provide an effective seal with conventional head gaskets, particularly in the zones at which the bores are most closely adjacent.
One of the concerns with head gaskets where bores are closely adjacent is that the gasket body portion disposed between the bores is relied on to provide a seal and, where armoring is used, to mount the armor, thereby to provide an effective seal. As the width of the gasket between the bores decreases, the gasket body becomes increasingly fragile. Thus it may break away altogether, or, if it is a typical laminated gasket body, it may delaminate and thereby become ineffective for the sealing functions for which it was designed.
Therefore head gaskets having improved sealing capacities, particularly gaskets for engines in which the cylinder bores are closely adjacent, is to be desired.